BMW M5 S38 3.8L H-Beam Connecting Rods are crafted from 4340 high tensile steel, engineered for high performance and extreme durability. The bushings are composed of aluminum-silicon/bronze material with a radial groove serving as an oil reservoir. These rods feature a "Ribbed pin end" to minimize pin end distortion under heavy inertial loads while reducing excess weight. They are shot peened to relieve stress and undergo multi-stage heat treatment to enhance rigidity. Tight production tolerances ensure perfect fitment and optimized oil clearances, with controlled bend and twist. Each rod includes ARP 2000 cap fasteners rated at 220,000 psi, with an optional ARP L19 material upgrade available at 260,000 psi, and the kit comes with ARP moly and full fitting instructions.

Additional Machining Processes

• Dowel sleeves for perfect fit and accurate re-assembling
• Lipped Cap Relief for improved big-end integrity at extreme applications
• Grooves in Thrust Face for weight reduction

Technical Features of ZRP Connecting Rods

• Two-Piece forging for great strength
• Shot Peening for improved fatigue life
• Magnaflux Inspection ensures material consistency meets high-quality standards
• Double ribbed caps for added support
• Multi-Stage Heat Treatment for maximum strength, dimensional stability, and fatigue life
• CNC machining for superior tolerances, precise to 0.0002″
• Center to center maintained under .001″ tolerance
• Finite Element Analysis (FEA) for computer-generated stress analysis of con rods
• Optimal balancing for weight-matched sets of ± 1 gram